Automatic bucket positioner



March 11, 1969 G. J. GOTH AUTOMATIC BUCKET POSITIONER Filed Feb. 28, 1967 VAYA' MM50/v, 55h15, 5A rcHEwf/e fr 145. Cnr/G.

March 11, 1969 G. J. GOTH 3,432,057

AUTOMATIC BUCKET Po'sITIoNER Filed Feb. 28, 1967 Sheet 2 0f 2 r) INVENTOR.

United States Patent O 10 Claims ABSTRACT F THE DISCLOSURE A material handling implement pivoted on a vehicle for movement between a dump position and load position through a hydraulic jack under the control of a spring-closed valve. An automatic control is provided for allowing the valve to close when the implement reaches the load position.

BACKGROUND OF THE INVENTION This invention relates to vehicle mounted material handling implement and more particularly to an automatic :control for positioning the implement relative to the vehicle.

In many conventional material handling implements, a bucket is pivotally carried at the end of lift arms or a boom which is raised and lowered with respect to a vehicle to move the bucket between the ground where it is loaded to an elevated position for carrying and dumping. The bucket is pivoted on the boom through a tilt linkage that is capbale of moving the bucket from a digging or loading position to a carry position and also capable of being pivoted forwardly to dump its contents. The lift and tilt mechanisms are usually hydraulically controlled with separate sets of cylinders or jacks and individual control valves selectively supplying fluid to each of the cylinders. The usual sequence of a loader operation is to load, raise, carry and dump. After the contents of the buckets have been dumped, the operator must lower the bucket to the ground and at the same time adjust the bucket from its dump position to its load position. Of course, it is well known that the bucket must be critically positioned relative to the ground when it is being returned to the digging or loading position.

SUMMARY OF THE INVENTION The primary object of the present invention is to provide automatic means for stopping the pivotal movement of an implement when it reaches a predetermined position.

Another object is to provide an improved automatic positioning device for a bucket loader which eliminates complicated connections between the movable and fixed elements of the loader.

A further object is to provide an improved mechanical control for releasing a control valve with electrical actuating meanstregulating the mechanical control.

Other objects and features of the invention will .become apparent when considered in conjunction with the following speciiication and the accompanying drawings wherein:

FIGURE 1 shows a side elevational view of a tractor loader incorporating the invention;

FIGURE 2 is an enlarged fragmentary side elevation view of the linkage connection between the control valve and the control lever;

FIGURE 3 is a fragmentary vertical view taken generally along linesy 3-3 of FIGURE 2;

FIGURE 4 is a fragmentary sectional view of the control valve of the mechanism;

FIGURE 5 is an enlarged fragmentary -view of the switch and actuating mechanism forming part of the electrical circuitry; and

FIGURE 6 shows the various positions of the control lever.

On the drawings:

FIGURE 1 of the drawings generally discloses a tractor or track-laying vehicle 10 having an upright xed support 12 Asupporting a loader assembly 14. The loader assembly 14 includes a lift arm or boom 16 pivotally supported at one end on the xed support 12 through a pin 18. The opposite end of the loader assembly includes a bucket assembly, generally designated at 20 having a bucket 22 pivoted at 24 to the opposite end of the lift arm 16. The bucket assembly 20 further includes a linkage comprising a pair of pivotally interconnected links 26 having their free ends respectively pivoted to the bucket 22 and the lift arms or boom 16. A hydraulic actuator or motor 30 has its cylinder 32 pivotally supported on one of the links 26 and its piston rod 34 pivoted to the lift arm 16. Hydraulic iluid is supplied to either end of the cylinder 32 through conduits 36 and 38.

The boom arms 16 are moved between raised and lowered positions through a hydraulic actuator or motor 40 having a cylinder 42 pivotally carried by the xed support 12 and its piston rod 44 secured to the boom or lift arm 16. Hydraulic tluid is supplied to opposite ends of the cylinder 42 through conduits (not shown). A cornpensating cylinder motor 50 has its piston rod 52 secured to the boom 16 and its cylinder connected through a linkage 54 to the lift cylinder 42. One end of the compensating cylinder is interconnected at 60 to the conduit 38 while the second -or opposite end is connected at 62 to the second conduit 36 which supply uid to the tilt or bucket cylinder 30.

Although the tractor loader includes a pair of lift arms, associated cylinder-s and linkages connected thereto, for purposes of simplicity, only one has been shown in the drawings. However, it is readily understood that the entire assembly is duplicated on the opposite side of the vehicle and the bucket.

Pressurized lluid is selectively admitted to opposite ends of the hydraulic actuators 30, 40 from a control valve assembly 70 having a tilt valve 72 and a lifting valve 74. The valve spools 72, 74 are selectively actuated through a common control lever 76 located in the operators compartment of a vehicle. For this purpose, a lever 76 includes a rst hub portion 78 pivoted on a bolt 80 carried by the vehicle housing. An arm 82 integrally formed with the hub 78 is connected to the valve spool 74 through a linkage 84.

The end of the lever or handle 76 includes a second hub portion pivoted on a member 92 disposed perpendicular to the bolt 80. The hub 92 has an integral extension 94 connected by a swivel joint 96 to an adjustable member 98 the lower end of which is secured to one end of a linkage plate 100 through a bolt 102. The linkage `plate 100 is pivotally mounted on a shaft 110 fixed on a plate 112 carried by the vehicle frame.

A `rst arrn 114 is formed integral with a hub 116 rotatably received on the shaft 110. The arm 114 is connected through a linkage 118 to the free end of the valve spool 72. A second arm 120 integral with hub 116 and arm 114 forms a bell crank 121 having its free end adapted to engage a stop 122 carried by the linkage plate 100. The Ibell crank is constantly urged into engagement with the stop 122 by a spring 125 having one end mounted on a pin 124 on arm 120 and the opposite end carried by a shaft 126 fixed to the linkage plate 100.

Thus, raising and lowering the control member 98 through the manually `operated lever 76 will pivot the bell crank and linkage plate as a unit about the shaft to move the valve spool 72 between neutral and operated positions. Likewise, movement of the hand operated lever in a second direction will actuate the second valve spool 74.

As was indicated above, the tilt or bucket valve spool is of the neutral self-restoring type and, during normal operation, the force required to overcome the spring centering force of the valve spool is provided by the interconnection between the control lever 76 and the valve spool 72. According to the invention, locking means are provided for maintaining the Valve spool in operative position and automatically restoring the valve spool to the neutral condition upon predetermined pivotal movement of the bucket on the boom. In the illustrated embodiment, the locking means 140 includes a crank 142 pivotally mounted on a shaft 144 secured to the main support Imember 112. One end of the crank 142 has a spring 146 secured thereto which is adapted to normally maintain the crank 142 in contacting engagement with an adjustable stop 148. The opposite end of the crank is provided with a contacting member or shaft 150 adapted to engage a portion of the shaft 126 carried by the linkage plate 100.

The crank 142 is adapted to be rotated clockwise to counteract the bias of the spring 146 by an electrically operated solenoid 160 having a plunger (not shown) adapted to engage the shaft 126 carried by the linkage plate 100. The solenoid 160 is actuated through a control means carried by the loader assembly. For this purpose, a telescoping tubular member including a rod 170 pivotally secured to the linkage 26 which forms part of the tilting mechanism for the bucket 22. The rod is slidably received within a tubular member 172 supported by an arm 174 pivoted to the boom 16 by pin 176. The free end of the tubular member 172 supports a limit switch 178. The normally open limit switch is connected to the solenoid 160 through suitable wiring (not shown). Preferably a second normally open limit switch 180 is connected in series with the solenoid 160 and switch 17 S. The second switch is xedly secured to the shaft with the actuating arm 182 of the switch disposed in the path of the shaft 126 carried by the linkage plate 100.

OPERATION During normal operation of the bucket loader, the control lever is moved through the neutral, dump and rollback positions shown in the control pattern of FIGURE 6. During this operation, the bell crank 121 and linkage plate 100 rotate as a unit and the locking means 140 is not effective. Thus, the control lever must be moved manually between actuated and neutral Ipositions and the forces of the linkage plate 100 and bell crank 121 will be sutlicient to cause the self-centering valve spool 72 to move from the operated to the neutral position.

However, if it is desired to automatically return the tilt spool to the neutral position upon predetermined pivotal movement of the bucket with respect to the boom, the control lever is moved to the roll-back (detented) position shown in FIGURE 6. This movement will rotate the linkage plate 100 counterclockwise on shaft 110` from the normal roll-back position shown in FIGURE 2 to have the shaft 150 in contacting engagement with the shaft 126 carried by the linkage plate. The shaft 126 will also contact the arm 132 of limit switc-h 180 to close the switch. During this counterclockwise rotation of linkage plate 100, the crank 121 will be maintained at substantially the position shown in FIGURE 2 since the valve spool, by previous movement to the roll-back actuated position, is not capable of being moved beyond this point. Thus, the spring 125 will be expanded and the combined action of this spring and the spring 146 will maintain the spool in the actuated position as well as the linkage plate in the locked position with the shaft 150 disposed below and in contacting engagement with shaft 126.

Upon predetermined counterclockwise pivotal movement of the bucket 22 on the boom arms 16, determined Cit by the length of indicator rod 170 forming part of telescoping member, this rod 170 will engage the actuating member (not shown) of limit switch 178 to close the switch and complete the circuit to the solenoid actuated plunger 160. This will force the plunger rig-htwardly as viewed in FIGURE 2 to rotate the crank 142 on shaft 144 and move shaft 150 out of contacting engagement with shaft 126 carried by the linkage plate. The tension of the spring 125 interconecting crank 121 and linkage plate will cause the linkage plate to be rotated clockwise about the shaft until the free end of the crank 121 engages stop 122. Thereafter, the crank 121 and linkage plate 100 will rotate clockwise as a unit and the selfcentering force of the spring biased spool 72 will move the spool to the neutral position.

It should be noted that while the control lever and the linkage plate 100 and latch 14() are in the detented condition, the latching spring 146 will resist the neutral self-restoring force of the valve spool. However, should the operator desire to manually neutralize the valve While it is in the operated detented position, the force of the latching spring can be overcome by manually forcing the control lever towards the neutral position. Thus, the mechanism is at all times capable of being manually released from the detented position.

By proper selection of the length of the control member or indicator rod secured to the linkage 26, the bucket can be moved to the return-to-dig position relative to the boom while the boom is being lowered from the dump position to the loading or digging position. Furthermore, by utilizing a single control lever in the operators compartment of the vehicle for actuation of both the lift valve spool and the tilt valve spool of the control valve assembly, the bucket movement can readily be controlled by one hand of the operator leaving the second hand free for maneuvering the Vehicle.

Also, by utilizing an electrically actuated control member at the valve, no complicated interconnections need be made between the fixed or vehicle portion of the loader and the movable or loader assembly. Also, by providing a second normally open limit switch adjacent the valve spool, the circuit to the solenoid will only be closed during the short period of time in which the boom carrying limit switch is actuated and the valve spool is moved to the neutral position. Thereafter, the second switch will be opened to de-energize the circuit to solenoid 160. This unique feature greatly increases the operating life of the ent-ire circuitry.

It should also be noted that the actuating mechanism is carried in a fixed position on the boom arms so that the bucket may be moved to the returnto-dig position while the loader arms or lift arms are being lowered from the dump to the digging position.

A-lthough the improved linkage connection has been shown as interconnecting the tilt valve with the control lever, it is readily apparent that this linkage could be duplicated for the lift valve connection to the control lever. Therefore, it would only be necessary to provide a switch actuated at the desired elevation of the boom arms on the vehicle to disrupt the fluid ow to the lift cylinder and thereby position the boom arms on the Vehicle in a predetermined height.

While a preferred embodiment of the invention has been shown and described, it will be understood that various changes and modifications may be made without departing from the spirit of the invention as defined by the following claims.

Iclaim:

1. An automatic positioning device for use with a vehicle having a bucket assembly pivotally mounted on the vehicle, hydraulic means including a neutral selfrestoring valve for pivoting the bucket assembly on the vehicle, and a control lever for activating said valve, the device comprising: linkage means interconnecting said control lever and said valve, locking means selectively engaging said linkage means for maintaining said valve in an operative condition, said linkage means being movable to a first position wherein said locking means is inoperative and said valve is controlled by the movement of said control lever and a second position beyond said first position wherein said locking means engages said linkage means and electrically operated means responsive to pivotal movement of said implement on said vehicle and loperable to release said locking means when said linkage means is in said second position and allow said linkage means to move from the second position and said valve to return to the neutral inoperative position whereby to position the implement in a predetermined position on said vehicle.

2. A device as defined in claim 1, wherein said electrically operated means includes a solenoid adjacent said linkage means, switch means connected to said solenoid, and means carried by said implement for actuating said switch means.

3. An automatic positioning device for use with a vehicle having a bucket assembly pivotally mounted on the vehicle, hydraulic means including a neutral self-restoring valve for pivoting the bucket assembly on the vehicle, and a control lever for activating said valve, the device comprising: linkage means interconnecting said control lever and said valve, locking means selectively engaging said linkage means for maintaining said valve in an operative condition and electrically operated means responsive to pivotal movement of said implement on said vehicle for releasing said locking means and allowing said valve to return to the neutral inoperative position whereby to position the implement in a predetermined position on said vehicle, said linkage means including a plate pivotally mounted on a fixed shaft, a crank pivoted on said shaft and having one end connected to said valve with the opposite end resiliently urged into contacting engagement with a portion of said plate.

4. A device as defined in claim 3, in which said locking means includes a pivoted member having a portion disposed in the path of said plate, means resiliently urging said member into said path, said electrically operated means including a solenoid, when actuated, urging said portion `of 4said member out of the path of said plate to allow movement of said plate causing said valve to be restored t-o the neutral position.

5. A device as defined in claim 4, wherein said electrically operated means includes `a first switch carried by said vehicle, a second switch carried by said linkage means and actuated when locking means engages said linkage means, a solenoid adjacent said locking means and an actuating member movable with said implement to actuate said first switch upon predetermined movement of said implement -on said vehicle to energize said solenoid and release said locking means, whereby said sec-ond switch will be opened when said valve is returned to the neutral position.

6. In a vehicle having an implement pivotally carried on a boom movable on said vehicle, a first fluid motor for pivoting said implement on said boom, a second fluid motor for moving said boom relative to said vehicle, first and second valves respectively connected in fiuid fow relation to said motors, a single control lever for moving both of said valves, first and second linkage means operatively connecting said control lever with each of said valves, means for mounting said lever for m-ovement in perpendicular paths whereby movement along one path `will actuate one of said valves while movement along the second path will actuate the -second of said valves, and locking means associated with at least one of said linkage means to lock at least one valve in operative position upon predetermined ymovement of said lever.

7. A vehicle as defined in claim 6, wherein said one linkage means includes first and second elements resiliently interconnected to move as a unit while said control lever is moved along one of said paths between first and second operated positions while said locking means remains inoperative and wherein movement of said control lever beyond one of said operated positions causes relative movement of said elements to have said locking means engage one of said elements thereby locking said associated valve in operative position.

l8. A vehicle as defined in claim 7, including electric means for rendering said locking means inoperative when said implement reaches a predetermined position on said boom allowing said one valve to move to its neutral position.

9. A vehicle as defined in claim 6, further comprising release means for said locking means including a solenoid adjacent said locking means, a switch operatively connected to said solenoid and means for actuating said switch energizing said solenoid upon predetermined movement of said implement on said jboom whereby said solenoid releases said locking means and allows said valve to move to the neutral position.

10. A vehicle as defined in claim `6, in which said one linkage means includes first and second elements mounted for pivotal movement on a comm-on axis with said first element coupled to `said one valve and said second element coupled to said control lever, biasing means resiliently urging said elements to a Ifirst position whereby said elements move as a unit and wherein predetermined movement `of said control lever will cause relative movement of said elements to a second position with said locking means engaging one of said elements and means for releasing said locking means upon predetermined movement of said implement on said vehicle to allow said ybiasing means to move said elements to a first position and said one valve to move to its neutral position.

References Citedl UNITED STATES PATENTS HUGO O. SCHULZ, Primary Examiner. 

